Catchable fatal error: Object of class WP_Error

Hello,

I’ve updated my wordpress with WordPress 3.0 and my home page doesn’t display correctly, I’ve got only the slideshow and the header working, the others things (like the sidebar, the featured post with thumbs, etc…) have disappeared.

I’ve deleted a category, could this be related to my problem ?

I’ve got this error message on some of my slideshow :

Catchable fatal error: Object of class WP_Error could not be converted to string in /home/www/27c1ef9161b34a18871e0306ccca0e4e/web/wp-content/themes/mymag/index.php on line 32

My index.php lines :

<div class=”title”>
<h2>cat_ID; echo get_category_link($category_id);?>”><?php echo $category[0]->cat_name;?> — <?php the_time(‘F j, Y’); ?> at <?php the_time(‘g:i a’); ?></h2>
<h1>” title=”<?php the_title();?>”><?php the_title();?></h1>
</div>
<div class=”arrow”></div>
</div>
<?php endwhile;?>
</div>
</div>

Best regards,